Revert "Drop broken and unnecessary RequiredInputRepresentation() in HMathFloorOfDiv."

This reverts r16190.

TBR=danno@chromium.org

Review URL: https://codereview.chromium.org/23188003

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@16191 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

src/hydrogen-instructions.h

@@ -3841,6 +3841,10 @@ class HMathFloorOfDiv: public HBinaryOperation {
 
   virtual HValue* EnsureAndPropagateNotMinusZero(BitVector* visited);
 
+  virtual Representation RequiredInputRepresentation(int index) {
+    return Representation::Integer32();
+  }
+
   DECLARE_CONCRETE_INSTRUCTION(MathFloorOfDiv)
 
  protected: